This is the first of a three-part series that looks back at the 30-year tenure of the U.S. space shuttle program.

"The orbiter is a completely different vehicle than anything that has ever flown in space. It was a work platform, a spacewalk platform, a construction site with a robotic arm, a laboratory, a people mover. It was a complex vehicle operating at the edge of its performance, with very little margin for error," John Shannon, program manager at the Johnson Space Center in Houston told Air & Space magazine in March.


Credit: NASA

When Atlantis returns home, it will mark the end of the post–lunar landing era in U.S. spaceflight—and an interruption in American-made access to space. Until either a replacement private- or public-sector spacecraft and launch system gets off the ground, American astronauts will have to hitch a ride on Russia's Soyuz capsule to go to and from the International Space Station (ISS)—a situation that would make any Cold Warrior gape in incredulity.


Cosmos interruptus

This is not the first time that there has been such an interlude. Between the last Apollo flight in 1975 and first shuttle launch in 1981, the U.S. did not have a spacecraft available to hurl humans into space. But unlike that hiatus, during which the shuttle was being developed, it is not as clear what route NASA will take to get back in the manned spaceflight business.

Until February 2010 the future of manned missions beyond the shuttle era, both in orbit and beyond to the moon and other celestial bodies, looked promising. The Constellation Program with its Orion crew capsule and Ares boosters announced by President George W. Bush in 2004 would have replaced the shuttle with a safer spacecraft, and one capable of leaving low Earth orbit to ferry crews to the moon and beyond by the end of this decade. Alas, it was canceled by the Obama administration last year. Many elements of Orion have been mostly resuscitated by Congress since then with the go-ahead in May to build the Apollo-alike and, Orion-based, but blandly renamed Multi-Purpose Crew Vehicle as well as develop a heavy-lift booster just as imaginatively dubbed the Space Launch System (almost as if to avoid attracting budget-cutters' attention). Plans for where to go and when to go, however, remain as iffy as the economy.

As for even getting people and materiel to and from the ISS, NASA is currently pinning its hopes on the private sector. Entrepreneur Elon Musk's SpaceX not only has sexier names for its vehicles—the Falcon 9 booster and Dragon crew and cargo capsules—but the system has shown promising results since its maiden launch in December 2010, where the Dragon orbited Earth twice and successfully reentered and was recovered. And according to the company's launch manifest, SpaceX plans to launch its first resupply mission to the ISS in 2012. A human crew will follow in 2014, Musk said in April in a company press release.


It orbits like a spaceship and lands like an airplane

In 1972 America was a moon-faring nation. It had spacecraft and hardware capable of taking humans to and from our nearest neighbor world, and NASA was ready to go at least three more times. But public approval and a budget-stressed administration thought it was act that was played out. President Richard Nixon, no fan of the moon program, canceled Apollo and set the U.S. on a path to build a reusable, heavy-lift space plane that would make access low Earth orbit almost routine. Although Apollo could carry people on a roundtrip to the moon, the shuttle would haul tons of cargo into orbit, sport a robotic arm for on-orbit construction, could land at an airport and be totally reusable. It also would have a larger living area for its crew with amenities such as a toilet and space for astronauts to stretch and float about, luxuries of which moon-farers in cramped capsules could only dream.

The real-world shuttle fell short on total reusability (its external fuel tank is discarded) but it nonetheless was a major departure from the way any country had accessed orbit. The winged craft covered with a reentry heat-shedding bulwark of fragile reentry tiles also was configured with military missions in mind. And the Pentagon was building classified surveillance satellites that would fit inside the shuttle's cargo bay. At 18 meters long, 4.5 meters wide, it was built to satisfy the National Reconnaissance Office, which wanted to make sure the Air Force's biggest satellites could   be carried. There were even plans to launch not only from Florida, but into polar orbit—the kind in which spy satellites fly—from Vandenberg Air Force base in California, something put to an end by the 1986 Challenger disaster, among other technical problems.

NASA exhausted its remaining Apollo hardware on the Skylab space station between 1973 and 1974, and the White House set out to explore not the lunar surface, but Cold War orbital détente with the Soviet Union in its highly publicized Apollo–Soyuz rendezvous in 1975. Meanwhile, on the ground, agency engineers were busy mixing and matching off-the-shelf technology with new techniques and materials to make an easily maintained and refitted vehicle with a short turnaround time that could routinely launch and land many times a year. By 1981 space shuttle Columbia was ready for its first foray into orbit. America was back in space—albeit low orbit.

Although the initial shuttle test flights were considered successful, weakness in the design became apparent. When STS 1, the first flight with veteran astronauts Commander John Young and Pilot Robert Crippen returned, it was found that 16 tiles were lost and 148 were damaged. Such a breach, if it happened in critical areas, could cause a shuttle and crew to burn up on reentry. Problems with the fragile heat shield tiles, surfaces and blankets taking damage by ice, foam and other flying debris shed by the craft during the violence of launch dogged the program throughout, and went from a nagging concern to a fatal failure with the loss of Columbia in 2003.

Long before that, of course, there was Challenger in 1986, and with its demise the shuttle system came to be derided by critics as nothing more than unjustifiably risky machine that was too expensive, overly complex, unreliable space truck that could only climb into low orbit around 3,300 kilometers high a half dozen times a year, NASA's space shuttle fleet has flown 134 missions since 1981, averaging 4.5 a year, including the one flight that remains (set to launch July 8).

FIRST LADY: Launched June 1983, Challenger carried five astronauts. The mission marked the first spaceflight of an American woman, Sally Ride. Pictured: Ride monitors control panels from the pilot’s chair on the flight deck. Credit: NASA

Shortcomings and disasters aside, during its tenure the space transportation system has accomplished a number of important goals beyond its most well-known and documented accomplishment, hauling up people and materials to contribute the lion's-share of the more than a decade long construction of the $100-billion International Space Station. But before the ISS, when it was being said by critics that the U.S. had a spaceship, but nowhere to go, shuttle crews were busy staging other firsts and forays. Non-ISS highlights of the shuttle era were also important milestones in the shuttle program legacy—as were, unfortunately, the disasters. 

Tomorrow, part 2—NASA's deadly reality-checks